1. Field of the Invention
The present invention relates to an electric socket and more particularly, to a safety electric socket, which has means to lock the blades (electrodes) of the inserted electric plug.
2. Description of the Related Art
An extension cable may be used to extend power supply from a wall outlet to a suitable location for the connection of the electric plug of an electric appliance. Frequently plugging the electric plug into the electric socket of the extension cable and deplugging the electric plug from the electric socket may cause loosening of the metal clamping plates of the electric socket or the metal blades of the electric plug. Loosening of the metal clamping plates of the electric socket or the metal blades of the electric plug may result in power failure of the electric appliance or a short circuit.
FIGS. 1 and 2 show an electric socket constructed according to Taiwan Patent Publication No. M261875, entitled “Electric Socket Locking Device”, which comprises a housing 91, a socket body 92, and a locking device 93. Rotating the rotary knob 931 of the locking device 93 to force its bottom protruding portion 9314 against the top protrusion 9323 of a pressure block 932, the pair of protrusions of a locking member 933 are moved with the locking member 933 over a protrusion 9324 of the pressure block 932 into a respective groove 9332 at the bottom side of the pressure block 932 for allowing downward movement of the pressure block 932, and therefore the clamping holes 9326 of the clamping feet 9325 of the pressure block 932 are forced into engagement with the metal blades 961 of the inserted electric plug, locking the inserted electric plug to the electric socket. On the contrary, rotating the rotary knob 931 of the locking device 93 in the reversed direction, the pair of protrusions of the locking member 933 are moved with the locking member 933 out of the respective grooves 9332 of the pressure block 932 over the a protrusion 9324 of the pressure block 932 to force the pressure block 932 upwards, thereby unlocking the inserted electric plug. According to this design, the rotary knob 931 of the locking device 93 protrudes over the top side of the housing 91 at a distance, increasing space occupation of the electric socket and destructing the sense of beauty.